The present invention relates to a pipe entry tool for cutting and entering a pipe or conduit.
Fiber optic cables are housed in a variety of ways in order to protect them from the harsh environments in which they are installed. For instance, fiber optic cables have been housed in PVC or metal pipes to protect them from unstable soil, from heavy traffic right of way, and in areas where the cable engineer feels that the cable may be in jeopardy. Once a cable is installed in its environment, it is often difficult to gain access to the fibers inside the cable for repair or maintenance.
It is often necessary to gain access to pipes, such as 2 or 4 inch diameter pipes, for example, for repair or maintenance purposes. These pipes are often located in tight quarters, but may also be located in open space environments. Presently, the tools available for cutting pipes are side grinders, power saws, or an assortment of nibblers. Each of these tools requires AC power in order to operate. Manholes and low-lying areas are not conducive to the use of power tools due to the possibility that explosive gases may be present, which may be ignited by a spark generated by the power tools. Thus, a manually operated tool is desirable in gaining access to pipes.
In addition, side grinders and power saws are undesirable in that they can be hazardous to the material inside the pipe due to spark discharge, blade fragmentation, and excessive depth of cut. Nibblers are useful on pipes which have sufficient interior space inside the pipe to accept the entrance of the nibbler foot, but many pipes, such as 2 or 4 inch pipes, often do not have ample interior space available to accept the nibbler foot. Current methods of opening pipes have been found to cause more harm than benefit. As a result, the fiber optic cable is often required to be put out of service for fear of damage to the unprotected fibers in the pipe or possible disruption of service. Thus, a tool is needed that allows quick access to fiber optic cables located within PVC or metal pipes and is simple to operate, safe for the operator, and unlikely to damage the fiber optic cables inside the pipe.
A large number of pipe sizes are utilized in housing cables. PVC and metal pipes typically range in diameter from about 2 to 12 inches, with 2 and 4 inch pipes being common, and usually have a wall thickness of about xe2x85x9 to xc2xc inch. Thus, it is desirable, to provide a single device which is capable of cutting a number of differently sized pipes.
Also, in gaining access to the interior of PVC or metal pipes, it is often desirable to cut a section out of the pipe, such as in the shape of a window, in order to perform operations on the cables installed inside the pipe. This requires cutting the pipe in both a longitudinal direction and a circumferential direction. A window can be formed by making two cuts in a circumferential manner and two cuts in a longitudinal manner, thereby freeing a substantially rectangular section of the pipe wall from the remainder of the wall. Thus, it is desirable to provide a device which can interchangeably cut a pipe in both the longitudinal and circumferential directions.
There are many types of manually operated pipe cutters known in the art. Typically these pipe cutters include a cutting wheel and rollers mounted on a curved frame which either entirely or partially surround the pipe and include a handle for turning the cutter. Some of the cutters rely on a spring for resiliently forcing the cutter into the conduit or pipe. Others employ an adjustable screw mechanism for forcing the cutting wheel into engagement with the pipe and for regulating the cutting force as the wheel penetrates the wall of the pipe.
A number of patents have issued that are directed toward manual devices for pipe cutting. For instance, U.S. Pat. No. 463,102 to Courtemanche discloses a cutting device with a single cutting blade which is capable of cutting a pipe in the circumferential direction. The device includes two separate pieces for surrounding a pipe to be cut, with a cutter being fixed to one piece and two rollers being fixed to the other piece. The two pieces are connected by a thumb screw and are adjustably movable relative to each other by adjusting the thumb screw. The device rotates about the pipe to be cut and the thumb screw is tightened down to bring the two pieces together to cut through the pipe. The cutter and rollers are fixed in position on the device.
French Pat. No. 492,691 and U.S. Pat. No. 691,649 to Mitchell each disclose a pipe cutting tool which includes two semicircular portions which form a ring for surrounding the pipe to be cut. Three cutting wheels are disposed in a triangular arrangement about the circumference of the ring. Each of the cutting wheels is adjustably positioned to move in and out relative to the pipe in order to move the cutting blades inwardly to cut the pipe. Cutting occurs in a circumferential manner.
U.S. Pat. No. 2,622,323 to Grimaldi discloses a pipe cutter which includes two semicircular portions which form a ring for surrounding the pipe to be cut. The device includes a single cutting wheel and two rollers. The rollers are positioned on a single bracket and are positioned opposite the cutting wheel on the ring. The cutting wheel and rollers are advanced to cut the pipe by turning screws upon which the cutting wheel and roller carriage are carried. Cutting is performed in a circumferential manner.
U.S. Pat. No. 4,078,304 to Netzel discloses a cutter for cutting corrugated pipe which includes two semicircular members hinged together to form a ring. A cutting wheel is fixed to one of the semicircular portions and four rollers are disposed at evenly spaced locations around the periphery of the ring for guiding the movement of the cutter around the pipe. The two semicircular portions are attached at one end by a pin which is biased-closed by a spring. The spring closure provides for adjustment to assist in cutting and the cutting wheel cuts in a circumferential manner.
U.S. Pat. No. 4,103,419 to Matthews et al. discloses a pipe cutter which includes two members pivoted together to form jaws which can be opened and closed. Each jaw is attached to an elongated portion. The elongated portions together form the handle of the device. Each jaw portion carries two rollers and a cutter is positioned on one of the jaws near one of the rollers. The cutter is adjustable to move inwardly to cut the pipe in a circumferential direction.
British Pat. No. 24,695 discloses a tool that is used to make either a single circumferential cut or a single longitudinal cut. In a first embodiment, the device includes a single cutter and two rollers, which are disposed in a triangular arrangement on a C-shaped member to accommodate one size of pipe. The cutter and rollers are disposed on brackets which are rotatable between the longitudinal and circumferential directions. In a second embodiment, the device includes three cutters which are disposed in a triangular arrangement on the C-shaped member and a single roller. The three cutters are utilized for cutting in the circumferential direction, with the roller acting as a stop. When operated in the longitudinal cutting direction, two of the three cutters are moved out of engagement with the pipe and cutting occurs between a single remaining cutting blade and a roller. In the second embodiment, the pipe rests on the roller. In both embodiments, the cutting wheels and rollers are substantially fixed in position to accommodate one size of pipe.
The present invention is directed to a pipe cutting device which includes a first supporting portion, a second supporting portion associated with the first supporting portion, and at least two cutters. The first and second supporting portions are configured and dimensioned to at least partially encircle an opening to encompass a pipe to be cut. The cutters are positioned on at least one of the first or second supporting portions for engaging a pipe to be cut and are interchangeably rotatable between a circumferential cutting direction to make a single circumferential cut and a longitudinal cutting direction to simultaneously make at least two longitudinal cuts. The device is movable relative to a pipe to be cut to cut the pipe interchangeably in either the longitudinal cutting direction or the circumferential cutting direction.
The device may also include at least one roller positioned on at least one of the first or second supporting portions. The roller is for engaging a pipe to be cut while the cutters concurrently engage the pipe to be cut. The roller may be disposed on a roller assembly, which includes a screw with a knob attached at an external end thereof and a bracket disposed at an interior end thereof. The screw extends through a screw carriage defined in one of the first or second supporting portions and the bracket holds the roller. The bracket and roller are interchangeably rotatable between the longitudinal cutting direction and the circumferential cutting direction.
In one embodiment of the invention, two cutters are positioned on the first supporting portion and a single roller is positioned on the second supporting portion. The two cutters and single roller are positioned in a substantially triangular arrangement relative to each other.
The cutters may be cutting wheels which rotate upon a central axis. When arranged in the longitudinal cutting direction, the cutting wheels are each preferably positioned substantially parallel to a radii of said pipe to create substantially parallel cuts. A cut is created for each cutting wheel.
In another embodiment of the invention, the first and second supporting portions together substantially encircle the opening to encompass a pipe to be cut. The first and second supporting portions are preferably substantially semicircular and a first end of the first supporting portion is preferably attached to a first end of the second supporting portion by a hinge pin. The second end of the first supporting portion may be associated with a second end of the second supporting portion by a locking mechanism for removably locking the first and second supporting portions together. The first and second supporting portions at the second ends thereof may have at least one hole in aligned relation with one another and the locking mechanism may include at least one locking pin for insertion into and removal from the aligned holes in the first and second supporting portions.
The device may include a cutter assembly for supporting each cutter. Each cutter assembly may include a housing with a screw carriage defined therethrough, a screw extending through the screw carriage, a knob disposed at an exterior end of the screw, and a single cutter disposed at an interior end of the screw. The knob of the cutter assembly may serve as a handle for rotating the device around a pipe. In this embodiment, at least one of the first and second supporting members includes a through slot extending radially therethrough. The slot includes an inwardly defined ledge, with the cutter assembly extending through the slot and the cutter housing seating on the inwardly defined ledge of the slot. The slot extends radially through the first supporting member and two cutter assemblies are positioned on the ledge defined in the slot. The cutters of the cutter assemblies extend through the slot and into the opening of the device for cutting engagement with a pipe. Each cutter assembly may be independently positionable within the slot at a plurality of locations.
Each cutter assembly may be secured to one of the first or second supporting portions by a retaining element. The retaining element may be a pin which extends through at least one hole defined axially through the cutter housing and one of the first supporting portion or second supporting portion. The cutter assembly may also include a bracket disposed at the interior end of the screw. The cutter is attached to the bracket by a pin. The bracket is interchangeably rotatable to rotate the cutter between a longitudinal cutting direction and a circumferential cutting direction.
The first and second supporting portions and cutters may be formed of a hardened steel.
The invention also includes a method for cutting a window out of a pipe wall. The method includes providing a pipe cutting device having at least two rotatable cutters which are interchangeably rotatable between a longitudinal cutting direction and a circumferential cutting direction and positioning the pipe cutting device substantially around a pipe to be cut with the cutters positioned for cutting in the longitudinal cutting direction. The pipe cutting device is moved longitudinally along the wall of the pipe to simultaneously make at least two longitudinal cuts through the pipe wall. The longitudinal cuts each have a first end and a second end which are substantially longitudinally aligned with one another. The pipe cutting device is positioned at the first end of the longitudinal cuts with the cutters positioned for cutting in the circumferential cutting direction. The pipe cutting device is moved circumferentially around at least a portion of the wall of the pipe at the first end of the longitudinal cuts to cut the pipe wall circumferentially substantially at least between the longitudinal cuts. Then the device is positioned at the second end of the longitudinal cuts with the cutters positioned for cutting in the circumferential cutting direction. The device is then moved circumferentially around at least a portion of the wall of the pipe at the second end of the longitudinal cuts to cut the pipe wall circumferentially substantially at least between the longitudinal cuts. The longitudinal cuts and two circumferential cuts together create a cut portion of said pipe wall which is removable from the pipe to expose an open window to an interior of the pipe.